Islamabad, Pakistan — A NATO helicopter strike along the Pakistani border today killed three Pakistani soldiers and appears to indicate a new willingness by coalition forces in Afghanistan to engage in a strategy of "hot pursuit" against militants operating from the relative safety of Pakistan.

The strike reportedly took place in Pakistan’s Kurram tribal agency, although NATO claims the attack took place in Afghan airspace. A second NATO helicopter attack in Kurram took place some hours later, according to the Pakistani daily Dawn.

NATO officers and Afghan politicians have long charged Pakistan, which is receiving $700 million in US military aid this year, with providing haven and occasional support to the Taliban planning attacks inside Afghanistan.

Pakistan temporarily suspended a key NATO supply route to Afghanistan in response to the strikes. Hours after the Torkham pass border crossing was closed, more than 100 NATO trucks were reportedly lined up and waiting to cross into Afghanistan.

The event

According to news reports, a Pakistani Frontier Constabulary post came under heavy fire for half an hour, with three soldiers killed and three injured. "The helicopters shelled the area for about 25 minutes. Three of our soldiers manning a border post were killed and three wounded," a security official told Reuters.

Thursday's airstrike is the latest in a series of coalition attacks on Pakistani soil. Kurram was struck by International Security Assistance Forces (ISAF) on Sept. 28, a day after 30 militants were killed in a strike on North Waziristan tribal agency.

The strikes have drawn a sharp reaction here, with Pakistani Interior Minister Rehman Malik telling reporters Thursday that Pakistan will be forced to go “beyond protest” in protecting its sovereignty.

“These [attacks] are deliberate, what are the reasons behind it? We are peaceful people … why should these attacks ... come on us?” he told reporters.

Pakistan has been long-criticized for its unwillingness to confront militants not seen as inimical to its own interests, particularly groups such as the Haqqani network in North Waziristan. The Taliban and Al Qaeda are widely believed to enjoy sanctuary in the tribal areas of Pakistan, which a recent RAND report said could be the insurgency's Achilles heal.

But a change of direction may ultimately place a great strain on relations with Pakistan and prove counterproductive, according to retired general Talat Masood.

“These attacks are very serious for Pakistan. It goes to show [coalition forces] are expanding their zone of conflict and violating Pakistan’s territorial sovereignty,” he says.

“This war against militants is not just a question of using force – you have to get the whole country to support you. You should not alienate the people in such a way which can be very harmful,” he says, adding that such strikes have the power to “destabilize” Pakistan.